Showing papers on "Channel (digital image) published in 1996"

Multi-modal method for locating objects in images

Abstract: A multi-modal method for locating objects in images wherein a tracking analysis is first performed using a plurality of channels which may comprise a shape channel, a color channel, and a motion channel. After a predetermined number of frames, intermediate feature representations are obtained from each channel and evaluated for reliability. Based on the evaluation of each channel, one or more channels are selected for additional tracking. The results of all representations are ultimately integrated into a final tracked output. Additionally, any of the channels may be calibrated using initial results obtained from one or more channels.

Asymmetric stereo-optic endoscope

Abstract: An endoscope for stereo-optically viewing an object comprises a tubular insertion portion (6A, 6B) characterized by a pair of adjacent asymmetric optical systems including a primary imaging channel (10) and a secondary imaging channel (12). Associated with each channel is a solid state electronic imaging means (68, 80) positioned to receive the images relayed by primary and secondary image-relaying means. The optical portion of the primary channel comprises a relatively large objective lens system (20) and a primary image relaying means (22) designed to provide sharply focussed first images. The optical portion of the secondary channel comprises a relatively small diameter objective lens system (24A) and a secondary image relaying means (26A) designed to relay enough light and image information to provide an acceptable stereoscopic capability.

Incorporating connected region labelling into automated image registration using mutual information

Abstract: The information theoretic measure of mutual information has been successfully applied to multi-modality medical image registration for several applications. There remain however; modality combinations for which mutual information derived from the occurrence of image intensities alone does not provide a distinct optimum at true registration. The authors propose an extension of the technique through the use of an additional information channel supplying region labelling information. These labels which can specify simple regional connectivity or express higher level anatomical knowledge, can be derived from the images being registered. The authors show how the mutual information measure can be extended to include an additional channel of region labelling, and demonstrate the effectiveness of this technique for the registration of MR and PET images of the pelvis.

Integrated circuit failure analysis using color voltage contrast

Abstract: A method and apparatus for analyzing failures in integrated circuits. A first image is obtained using an emission or electron microscope while an integrated circuit is operating under a first set of conditions. The image is integrated for improved resolution with a camera in front of the microscope screen or with a digitizer coupled to receive video signals from the microscope. The first image is digitized and stored in a first channel of an RGB digitizer board and displayed on a display screen. A second image is obtained in the same way and is digitized and stored in a second channel of the RGB digitizer board and displayed on the display screen. The remaining channel of the RGB digitizer board is coupled to receive live images. The resulting combined image appears as a black and white image so long as the images are aligned. Any differences between the three images will appear conspicuously in color. The input logic levels to the integrated circuit are changed. Nodes having changed logic levels will appear in color in the display because they will only affect the third channel. In addition, the displayed image will simultaneously show nodes which have not changed states in different shades of grey depending upon the unchanged logic level. The displayed image may then be compared to a previously obtained reference image from an integrated circuit known to not have any defects. Any differences between the two images will indicate the exact location of a failure or defect.

Multichannel single-output color pattern recognition by use of a joint-transform correlator.

Abstract: A novel method for performing color image recognition by the use of the coherent joint-transform correlator is introduced The input plane of the proposed method is a spatial rearrangement of the separation into color channels of both the color input scene and the color target This input plane is gray scaled and monochromatic, thus it can be displayed by the use of amplitude spatial light modulators to achieve real-time operation The system provides a single output-plane result of the optical coherent addition of the separate channels’ correlation outputs At the output plane no electronic postprocessing is needed, and the detection decision is achieved simply by the application of threshold detection Experimental results and computer simulations are presented to demonstrate the abilities of this system

Image processing apparatus and methods

Abstract: An image processor receives color signals representing a color or black-and-white image, typically containing text and non-text areas. A sliding window or swath of the image is processed which progressively moves over the virtual image. A spatial filter is applied to sharpen the image and it is then classified into text and non-text regions. The data from the text regions is subjected to a black text enhancement process in which the color signal from a single channel (here the green channel) is thresholded against two thresholds, T1, T2. The lower (darker) threshold T2 identifies pixels for being set to black, whereas the threshold T1 identifies “support” pixels used in component connectivity analysis. Having defined a connected component using both T1 and T2 pixels, the color statistics of the pixels making up the component are analyzed to determine whether the component should be rendered black. If so, the image data is enhanced by snapping the T2 pixels to black, and snapping a halo of pixels around the black text component to white.

Robust speech processing with affine transform replicated data

Abstract: The present invention relates to a robust speech processing method and system which models channel and noise variations with affine transforms to reduce mismatched conditions between training and testing. The affine transform relating the training vectors C k with the vectors for testing condition c k' , is represented by the form: c'.sub.k.sup.T =Ac.sub.k.sup.T +b for k=1 to N in which A is a matrix of predicator coefficients representing noise distortions and vector b represents channel distortions. Alternatively, an affine invariant cepstrum is generated during testing and training for modeling speech to account for noise and channel effects. From the improved speech processing, improved speaker recognition with channel and noise variations is obtained.

Detection method using distributed read and integration cycles for scanning camera and corresponding detection array

Abstract: Disclosed is a detection method and a corresponding array architecture comprising sensors positioned according to a particular geometry, enabling the integration of a circuit for the management of the integration cycles and of transfers of charges between injection-integration circuits and TDI type summation circuits in the focal plane of the array. The array is fitted into a scanning camera that scans in a particular direction. The camera is designed to form a video signal for an image made up of pixels spaced out at a pitch p p with a value corresponding to the standard. The array has several rows of elementary sensors. The the sensors that belong to different rows and are aligned in the scanning direction define a detection channel V k . The spatial pitch p c of one and the same detection channel has a value that differs from the value of the pixel pitch p p by a fraction of this pixel pitch such that a sensor-pixel coincidence, which is achieved for a reference sensor C 0 , is no longer synchronous for any other sensor exposed to the same elementary field of view.

Development of a three-channel SWIR camera, for ground-based astronomical imaging. (Two micron all sky survey, 2MASS)

Abstract: The two micron all sky survey (2MASS) project, currently underway, requires a camera mated to a 13 meter Cassegrain telescope that will simultaneously image the J, H and Ks spectral bands onto three separate NICMOS3 HgCdTe detector arrays Dichroic beamsplitters allow the three FPAs to view the same field simultaneously This paper reviews the development of this camera, presents a detailed analysis of the optical design, and discusses the techniques used to align the instrument and evaluate its performance The low irradiance of astronomical sources, combined with background limited performance of the detectors, mandated a reimaging configuration and the enclosure of the camera optics within the cold volume Correcting chromatic aberrations, and minimizing ghost images were additional challenges imposed by program requirements The key to achieving high performance was found to be the selection of lens materials The final F/35 optical design uses fifteen CaF2 elements and four Infrasil elements in an all-spherical configuration The design is diffraction limited over the full format in the Ks spectral band, and is nearly so in the J and H bands The tolerance environment is benign, making the design well suited for use in a cryogenic environment A single channel prototype has been built and extensively field tested at the 50-inch telescope at Kitt Peak National Observatory Each channel in the multi-spectral camera uses the same optical design successfully demonstrated in the prototype Currently, the first of two three-channel cameras is undergoing lab tests for image quality and channel registration© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering Downloading of the abstract is permitted for personal use only

Statistical analysis of a subspace method for blind channel identification

Abstract: This paper considers the problem of blind channel estimation of multi-channel FIR filters. This is a problem arising in, for example, mobile communication systems using digital signalling. By using the orthogonality property between the noise subspace and the channel matrix, it has been shown in earlier work that the channel matrix is identifiable up to a multiplicative constant. In this article, the asymptotic properties of a subspace method using this orthogonality property is presented. An asymptotically correct weighting matrix is derived, demonstrating an attainable lower theoretical bound using the subspace estimate.

Detection and correction of bad pixels in hyperspectral sensors

Abstract: Hyperspectral sensors may use a 2D array such that one direction across the array is spatial and the other direction is spectral. Any pixels therein having very poor signal-to-noise performance must have their values replaced. Because of the anisotropic nature of information at the array, common image processing techniques should not be used. A bad-pixel replacement algorithm has been developed which uses the information closest in both spectral and spatial sense to obtain a value which has both the spectral and reflectance properties of the adjacent terrain in the image. A simple and fast implementation that `repairs' individual bad pixels or clusters of bad pixels has three steps; the first two steps are done only once: (1) Pixels are flagged as `bad' if their noise level or responsivity fall outside acceptable limits for their spectral channel. (2) For each bad pixel, the minimum-sized surrounding rectangle is determined that has good pixels at all 4 corners and at the 4 edge-points where the row/column of the bad pixel intersect the rectangle boundary (five cases are possible due to bad pixels near an edge or corner of the detector array); the specifications of this rectangle are saved. (3) After a detector data frame has been radiometrically corrected (dark subtraction and gain corrections), the spectral shapes represented by the rectangle edges extending in the dispersion direction are averaged; this shape is then interpolated through the two pixels in the other edges of the rectangle. This algorithm has been implemented for HYDICE.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Three-dimensional image system

Abstract: A multi-view three-dimensional image system that enables a plurality of observers to view a three-dimensional image simultaneously in the visible ray range without the utilization of special spectacles adapted for viewing three-dimensional images. The multi-view three-dimensional image system according to the present invention comprises an imaging apparatus wherein a plurality of vertical strip type electro-optic switches functioning as moving apertures are adjacently disposed in front of an object lens. The system also comprises a display apparatus which comprises an image projector having electro-optic switches and a projection lens similar to that in the imaging apparatus, a signal converter which converts a parallel signal to a serial signal, and a display having a holographic screen which displays a projected image. The imaging apparatus and the image projector acquire the image of objects and projects it through the vertical strip type electro-optic switches. The vertical strip type optical switches are opened or closed, for example, from right to left or from left to right 30 times per second. Since the vertical strip type electro-optic switches of the imaging apparatus function as moving apertures, the cross-sections viewed through adjacent vertical strip type electro-optic switch are slightly different. The image viewed through each vertical strip type electro-optic switch is recorded on the corresponding channel of the multi-channel video recorder. The signal converter of the image display apparatus makes the output of the multi-channel video recorder the same as the output of the camera utilized when acquiring the image. Since sub-view zones are defined by the vertical strip type electro-optic switches in the view-zone generated by the holographic screen, the three-dimensional image can be viewed at a number of points.

Multichannel image identification and restoration using the expectation-maximization algorithm

Abstract: Previous work has demonstrated the effectiveness of the expectation-maximization algorithm to restore noisy and blurred single- channel images and simultaneously identify its blur. In addition, a gen- eral framework for processing multichannel images using single-channel techniques has been developed. The authors combine and extend the two approaches to the simultaneous blur identification and restoration of multichannel images. Explicit equations for that purpose are developed for the general case when cross-channel degradations are present. An important difference from the single-channel problem is that the cross power spectra are complex quantities, which further complicates the analysis of the algorithm. The proposed algorithm is very effective at restoring multichannel images, as is demonstrated experimentally.

Apparatus and method for inspecting box blanks

Abstract: An apparatus and method for inspecting skived glue, hemming and skew, and backfold of cartons by means of real time image comparison. The apparatus comprises channel sensors, means for measuring conveyor travel distance, a system controller coupled to the channel sensors, a memory for storing images, a processor coupled to the outputs of the system controller and the memory and a bad carton locator means. A known good carton is passed through the channel sensors and a reference synthetic image is stored in a memory. A test carton is passed through the channel sensors producing a real time image which is compared to the stored reference synthetic image for detecting defects.

Segmented cold cathode display panel

Abstract: The present invention is a video display device that utilizes the novel concept of generating an electronically controlled pattern of electron emission at the output of a segmented photocathode. This pattern of electron emission is amplified via a channel plate. The result is that an intense electronic image can be accelerated toward a phosphor thus creating a bright video image. This novel arrangement allows for one to provide a full color flat video display capable of implementation in large formats. In an alternate arrangement, the present invention is provided without the channel plate and a porous conducting surface is provided instead. In this alternate arrangement, the brightness of the image is reduced but the cost of the overall device is significantly lowered because fabrication complexity is significantly decreased.

Digital mammography: hybrid M-channel wavelet transform for microcalcification segmentation

Abstract: A novel algorithm is proposed for the automatic segmentation of microcalcification clusters (MCCs) in digital mammography The hybrid method involves the use of a nonlinear filter for image noise suppression, coupled with wavelet transforms for image decomposition and an adaptive method for selective subimage reconstruction as a basis for segmentation of MCCs The use of M=2,3,4 and 8 channel wavelet transforms are evaluated to determine if the sensitivity of detection of MCCs can be improved and if the selective reconstruction of the higher order M/sup 2/ subimages allows better preservation of the segmented MCCs as required for their classification The M=2,3,4 and 8 wavelet transforms are implemented on different filter bank structures to determine if their computational efficiency can be improved while retaining properties such as near perfect reconstruction, namely polyphase quadrature mirror filters (QMF), tree structure and lattice structure

Coordinate transformation method for binary image

Abstract: A binary image coordinate transformation method can simplify the transformation processing for those portions consisting of pixels having the same single color value, thereby increasing the processing speed of binary image transformation overall. The original image is divided into a plurality of sub-regions. For each sub-region, it is detected whether or not the sub-region consists of pixels having the same color value of two color values of a binary image. The post-transformed image is divided into a plurality of sub-blocks. For each sub-block, all the sub-regions containing pixels corresponding to those pixels included in a sub-block are detected. When it is determined that the all the detected sub-regions corresponding to the sub-block have the same color value, the sub-block of the post-transformed image is covered with that single color in one go.

Single-channel polychromatic pattern recognition by the use of a joint-transform correlator.

Abstract: We present a single-channel system for color image recognition that is based on a joint-transform correlator setup. The color images are encoded as phase and amplitude functions, inspired from the Munsell color representation. A real-time implementation of the new codification method can be achieved by the use of a spatial light modulator operating in phase-only modulation mode. We determine the optimal codification for a linear color-phase code. Its performance is compared with a conventional multichannel correlator by means of computer simulations. Experimental results are also presented.

A restoration algorithm for P-32 and Y-90 bremsstrahlung emission nuclear imaging: a wavelet-neural network approach.

Abstract: A novel wavelet‐based neural network (WNN) filter is proposed for image restoration as required for imaging of beta emitters by bremsstrahlung detection using a gamma camera. Quantitative imaging of beta emitters is important for the in vivo management of antibody therapy using either P‐32 or Y‐90. The theoretical basis for the general case for M‐channel multiresolution wavelet decomposition of the nuclear image into different subimages is developed with the objective of isolating the signal from noise. A modified Hopfield neural network (NN) architecture is then used for multichannel image restoration using the dominant signal subimages. The NN model avoids the common inverse problem associated with other image restoration filters such as the Wiener filter. The relative performance of the WNN for image restoration, for M=2 channel, is compared to a previously reported order statistic neural network hybrid (OSNNH) filter. Initially simulated degraded images of known structures with different noise levels are used. Quantitative metrics such as the normalized mean square error (NMSE) and signal‐to‐noise ratio (SNR) are used to compare filter performance. The WNN yields comparable results for image restoration with suggested slightly better performance for the images with higher noise levels as often encountered in bremsstrahlung detection. Attenuation measurements were performed using two radionuclides, 32P and90Y as required for calibration of the gamma camera for quantitative measurements. Similar values for an effective attenuation coefficient were observed for the restored images using the OSNNH filters (32P: μ=0.122 cm−1, 90Y: μ=0.135 cm−1) and WNN (32P: μ=0.122 cm−1, 90Y: μ=0.135 cm−1) filters with slightly higher values obtained for the raw data (32P: μ=0.142 cm−1, 90Y: μ=0.142 cm−1) for a 3.5‐cm source size. The WNN, however, was computationally more efficient by a factor of 4 to 6 compared to the OSNNH filter. The filter architecture, in turn, is also optimum for parallel processing or VLSI implementation as required for planar and particularly for SPECT mode of detection.

Extracting essential modulated image structure

Abstract: We present a new theory of multidimensional AM-FM image modeling and derive algorithms for extracting AM-FM sub-image information from digital images. In contrast to Fourier components, AM-FM image functions admit arbitrarily varying amplitude and phase modulations. Thus, they are inherently capable of efficiently capturing essential nonstationary image structures. Often, such nonstationarities contribute significantly to visual perception and interpretation. We describe a practical approach for computing AM-FM image representations using nonlinear demodulation operators. A Gabor filterbank isolates components locally, and optimal filters based on a statistical state-space component model are used to trade image multi-components across the filterbank channel responses. We present dramatic examples where the essential structure of natural images is successfully recovered from their computed AM-FM representations.

STABIL: a system for monitoring persons in image sequences

Abstract: The proposed system STABIL combines four levels of abstraction. In the first level the foreground is extracted by using a Kalman filter technique. The second level uses the foreground regions in order to seek subsequently for parts of the skin of a human. The three channel color signal is transformed into a 2D color space best representing the color of the skin. The Kalman-filtering speeds up the classification in the case of a stationary camera; in the case of a moving camera the classification is directly applied on the sequence. The regions representing the skin serve as input for the third level estimating the position of the person in the 3D space relative to the camera. The fourth level handles a model of a human using statistical data of their size. The model is adapted to a person in an iterative process taking into account the limits of the movements of the person, the restrictions on the model in order to match the skin regions in the image to the correct person. The result of processing the n-the image of an image sequence is a scaled model projected and superimposed on the n-1-th image showing the correct estimation of the position of the person.© (1996) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Propagation modeling in land mobile satellite systems using photogrammetry

Abstract: We present a system that substitutes video image processing for propagation measurements and permits flexible fade simulation of land mobile satellite communication (LMSC) systems. Our method is based on deriving environmental characteristics from fisheye lens videos, using image processing algorithms. We employ the processed images to track the propagation state (clear, shadowed by vegetation or blocked) along the satellite-Earth communication path. Analyzing sequences of images results in a propagation state time series which is input to a channel simulator. In this paper, we present the optical measurement system, the image processing algorithms and channel simulation procedures. Finally, we compare simulation results with actual satellite fade measurements.

An image pre-processor in a device for direct electrostatic printing

Abstract: An image preprocessor is disclosed for a DEP device, wherein the image preprocessor corrects digital image data before printing. The image pre-processor preferably performs at least one the following steps : 1. correcting the image input density according to a first look up table (LUT) for obtaining a desired grey scale value, 2. correcting grey scale values by a second LUT for varying toner fluxes 111 through different printing apertures 107, said second LUT being desirable for adjusting the toner flux 111 to the differing distance of printing apertures 107 belonging to different rows of apertures 107, and for adjusting the toner flux 111 through various printing apertures 107 having varying aperture diameter or shape. This is referred to as a shading correction in a direction orthogonal to the print direction), 3. correcting grey scale value for the grey scale values of neighbouring pixels, that influence the toner flux 111 for forming the actual image pixel, referred to as neighbour compensation, 4. correcting grey scale values for the image density that has been printed through the individual printing aperture 107 prior to the actual printing the required pixel, called previous compensation, 5. correcting grey scale values for the hardware design of the printhead structure 106, i.e. assignment of image pixels to controlling IC number and output channel number per IC, 6. expressing grey scale values as a time modulated or voltage modulated output signal, 7. transferring image output signals in a serial data stream to a FIFO memory from which the output signals are preferably converted to a parallel data stream that is fed to driving IC's, that are used to put a voltage to the individual control electrodes 106a of the printhead structure 106 in the DEP device 100.

Channel normalisation by using rasta filtering and the dynamic cepstrum for automatic speech recognition over the phone

Abstract: Human auditory perception is perfectly capable to deal with time-invariant linear filter effects, such as those introduced by telephone handsets and telephone channels. We compared two different schemes for modeling human auditory time-frequency masking: RASTA filtering and the dynamic cepstrum represen­ tation (DCR). We used a small set of context-independent phone hidden Markov models for a recognition task of connected digit strings over the telephone. We found that RASTA filtering out­ performed the Gaussian DCR approach, despite the fact that RASTA represents a more crude approximation of human for­ ward masking. Our results may be influenced by the choice of the mel-frequency cepstral representation that we used. The superiour performance of the RASTA technique may also be ex­ plained by the fact that the frequency response of the RASTA filter is better matched to the region of modulation frequencies where human auditory perception is most sensitive.

Resolution enhancement of color video

Abstract: In this paper, an approach to improve the spatial resolution of color video is presented. Such high resolution images are desired, for example, in video printing. Previous work has shown that the most important step in achieving high quality results is the accuracy of the motion field. It is well known that motion estimation is an ill-posed problem. However, in processing color video, additional information contained in the color channels may be used to improve the accuracy of the motion field over the motion field obtained with the use of only one channel. In turn, this improvement in the motion field will be shown through several experimental results to significantly improve the estimation of a high resolution image sequence from a corresponding observed low resolution sequence.

Moving image communication conference system and its communication method

Abstract: PURPOSE: To provide the moving image communication conference system in which an image in a natural state is obtained and reality is not lost while emphasizing an image of an utterance party by keeping image quality in an excellent way while utilizing effectively an existing channel. CONSTITUTION: Terminal equipments 11-14 are provided with two moving image capture compression programs whose compression rate differs from each other and a decoding program decoding compressed motion image data sent through a network 10. In the case of the usual mode, the program with higher compression rate in the two moving image capture compression programs is used to compress a moving image and in the case of the utterance mode, the moving image is compressed by using the program with a low compression rate and the compressed image data sent through the network 10 are decoded by a decoding program and the decoded image data are displayed on display sections 11c-14c.

Toward high-resolution imaging with a simple adaptive-optics system

Abstract: High-resolution imaging with reference to a widely separated star is examined. Peak tracking of the specklegram in the reference channel results in a high-resolution image in the observational channel. A binary star with angular separation of 30.5 arcsec is examined in white light, and the resultant image of the primary star obtained with reference to the secondary star is shown to have better resolution than the centroid tracking image by a factor of 3.